Support static call by 'Call' mechanism about thincrest

[dakusui]

Following is an example to call static method.

      Function<Object, String> func = call(String.class, "format", "<me=%s, %s>", varargs(THIS, "hello")).$();

      System.out.println(func.toString());
      System.out.println(func.apply("world"));
      Crest.assertThat(
          func,
          allOf(
              Crest.asString("toString").equalTo("@String.format[<me=%s, %s>, Object:varargs[(THIS), hello]]").$(),
              Crest.asString(call("apply", "world").$()).equalTo("<me=world, hello>").$()
          )
      );

[dakusui]

Not only that, we are now able to call an instance method not on a target object by following way.

      Function<Object, String> func = callOn("Hello world", "indexOf", THIS).andThen("toString").$();

      System.out.println(func.toString());
      System.out.println(func.apply("world"));
      Crest.assertThat(
          func,
          allOf(
              Crest.asString("toString").equalTo("Hello world@indexOf[(THIS)]->@toString[]").$(),
              Crest.asString(call("apply", "world").$()).equalTo("6").$()
          )
      );